title: Disturbed adiponectin – AMPK system in skeletal muscle of patients with metabolic syndrome.
abstract: Patients with metabolic syndrome are characterized by low circulating adiponectin levels and reduced adiponectin sensitivity in skeletal muscles. Through binding on its main skeletal muscle receptor AdipoR1, adiponectin activates AMP-activated protein kinase (AMPK), a key player in energy homeostasis. Fourteen metabolic syndrome patients and seven healthy control subjects were included. Blood samples were taken to determine insulin resistance, adiponectin, lipoproteins, and C-reactive protein. Muscle biopsies (m. vastus lateralis) were obtained to assess mRNA expression of AdipoR1 and both AMPKα1 and AMPKα2 subunits, as well as downstream targets in lipid and glucose metabolism. Skeletal muscle mRNA expression of AMPKα1 and AMPKα2 was lower in metabolic syndrome patients (100 ± 6 vs. 122 ± 8 AU, p = 0.030 and 64 ± 4 vs. 85 ± 9 AU, p = 0.044, respectively), whereas the expression of AdipoR1 was upregulated (138 ± 9 vs. 105 ± 7, p = 0.012). AMPKα1 and AdipoR1 correlated positively in both the control (r = 0.964, p < 0.001) and the metabolic syndrome group (r = 0.600, p = 0.023). However, this relation was shifted upwards in metabolic syndrome patients, indicating increased AdipoR1mRNA expression for a similar AMPKα1 expression. Previously, a blunted stimulatory effect of adiponectin on AMPK activation has been shown in metabolic syndrome patients. The present data suggest that the disturbed interaction of adiponectin with AMPK is located downstream of the AdipoR1 receptor.
authors.affiliation: Antwerp University Hospital, Edegem, Belgium an.vanberendoncks@ua.ac.be.
authors.forename: An M
authors.initials: AM
authors.lastname: Van Berendoncks
authors.affiliation: Norwegian University of Science and Technology, Trondheim, Norway.
authors.forename: Dorthe
authors.initials: D
authors.lastname: Stensvold
authors.affiliation: University Paris-Sud, Châtenay-Malabry, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Garnier
authors.affiliation: University Paris-Sud, Châtenay-Malabry, France.
authors.forename: Dominique
authors.initials: D
authors.lastname: Fortin
authors.affiliation: Antwerp University Hospital, Edegem, Belgium.
authors.forename: Tahnee
authors.initials: T
authors.lastname: Sente
authors.affiliation: Antwerp University Hospital, Edegem, Belgium.
authors.forename: Christiaan J
authors.initials: CJ
authors.lastname: Vrints
authors.affiliation: Norwegian University of Science and Technology, Trondheim, Norway.
authors.forename: Slørdahl Stig
authors.initials: SS
authors.lastname: Arild
authors.affiliation: University Paris-Sud, Châtenay-Malabry, France.
authors.forename: Renee
authors.initials: R
authors.lastname: Ventura-Clapier
authors.affiliation: Norwegian University of Science and Technology, Trondheim, Norway.
authors.forename: Ulrik
authors.initials: U
authors.lastname: Wisløff
authors.affiliation: Antwerp University Hospital, Edegem, Belgium.
authors.forename: Viviane M
authors.initials: VM
authors.lastname: Conraads
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000235:genetics*; D052242:Adiponectin / Q000097:blood*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D024821:Metabolic Syndrome / Q000097:blood / Q000235:genetics*; D018482:Muscle, Skeletal / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D054419:Receptors, Adiponectin / Q000235:genetics*
chemical_list: C475418:ADIPOR1 protein, human; D052242:Adiponectin; D012333:RNA, Messenger; D054419:Receptors, Adiponectin; C526181:PRKAA2 protein, human; D055372:AMP-Activated Protein Kinases; C526180:PRKAA1 protein, human
keywords: AMPK; Adiponectin; metabolic syndrome; skeletal muscle